Children in America's inner cities are exposed to multiple known and potential neurodevelopmental toxicants. The overall goal of this project is to examine associations between exposures to EDs, pesticides and PCBs and growth and development of children of an already existing racially and ethnically diverse urban cohort of mothers and children. This project will continue to assess the effects of prenatal exposures to organophosphates (including chlorpyrifos), pyrethroids, and PCBs on growth and neurobehavioral development. As a new direction, the investigators plan to assess the impacts of potentially endocrine disrupting chemicals, specifically phthalates and bisphenol A on fetal, infant and childhood growth and development. Currently, they have at least 300 actively participating mother?infant pairs and will add another 78 mothers and infants from a community intervention project in the previous cycle of this grant. To assess environmental exposure, both stored and newly collected maternal and infant urinary samples will be used along with questionnaires. Tests to assess neurodevelopment include the Brazelton Neonatal Behavior Assessment Scale at birth, the Bayley Scales of Infant Development at ages 1 and 2 years, and several additional tests at ages 4, 6 and 7 years. Growth measures include indices of fetal growth (weight, head circumference and length at birth) as well as weight, head circumference, and length at ages 1, 2, 4, 6, and 7 years and percent body fat and lean mass at ages 4, 6, and 7 years. In collaboration with Project 3, the investigators will also assess possible modulating influences of polymorphisms and enzymatic activity involving paraoxonases, lipases and glucuronidases on these associations. The unique contribution of this study is that it assesses the effects on childhood growth and neurodevelopment of current multiple potential exposures to developmental toxicants among inner city, minority children.